I looked at the Jan Durand b4c3 link back in 2008-2010 when I just started out and could not find any trace or documentation to support the idea -- and there was the death notice with the birth location of "Uitlander". There is also a cover letter for the death notice, filed under KAB MOOC 6/9/14 Ref 3015 (not 3025) signed on 2 Nov 1838, stating that he left a will, according to his wife. I have not been able to locate the will. Has anybody else sighted this document? I have also not been able to find Johanna Magrieta Steenkamp's death notice.
The argument in the linked article is pretty convincing... I think they had me at the description of him as a "driftige redenaar" :-)
I believe the only way we will be able to prove or disprove this link will be through DNA testing.